Soil chemical properties following a one‐time spent drilling mud application on native prairie

Abstract

AbstractLandspraying while drilling (LWD) is an approved disposal method for water‐based drilling mud (WBM) systems in western Canada, where the mud is applied either on arable or vegetated land. This study examined the effects of a single LWD application (0, 15, 20, 40, or 80 m3 ha−1) on native prairie soil properties. Results from the study showed a significant increase in Na concentration and sodium adsorption ratio (SAR) in the 0‐ to 7.5‐cm depth. However, the highest SAR attained (3.46) after application at the 80 m3 ha−1 rate remained below levels considered detrimental to soil structure. Electrical conductivity (EC) also increased with the LWD rate but peaked at levels (447 μS cm−1 in the 0‐ to 2.5‐cm depth) much lower than the threshold for most plant species, and the effects on EC had disappeared by the end of the first year of mud application. Available P concentration (modified Kelowna method), averaged across sampling times and the two depths (0‐ to 2.5‐ and 2.5‐ to 7.5‐cm), increased from 7.4 to 11 mg kg−1 as LWD rate increased from 0 to 80 m3 ha−1. Although the available P remained at concentrations suboptimum for most crops, such concentrations may impact native prairie vegetation adapted to very low P. Drilling mud applications generally had no significant effect on available N. The application of WBM systems on the native prairie at recommended rates in western Canada may not be detrimental to soil quality and plant growth in this ecosystem.